The present invention relates to a semiconductor integrated circuit device including decoupling capacitors for reducing power supply noise.
In a semiconductor integrated circuit device, decoupling capacitors may be formed between power supply wires to reduce power supply noise. A decoupling capacitor can be formed with a gate oxide film. However, an increase in standby current, which results from gate leak current, cannot be ignored. Accordingly, decoupling capacitors are formed by using capacitors between power supply wires.
Various examples of decoupling capacitors formed between power supply wires have been proposed.
Japanese Laid-Open Patent Publication No. 2002-324841 describes a contact wire for connecting high potential power supply wires and a contact wire for connecting lower potential power supply wires. A capacitor is formed on an interlayer insulative film located between the contact wires.
Japanese Laid-Open Patent Publication No. 2001-177056 describes a high potential power supply wire and a low potential power supply wire included in multiple layers of power supply wires. The high potential power supply wire and the low potential power supply wire each include a capacitor power supply wire extending in a planar direction and a thicknesswise direction of a substrate.
Japanese Laid-Open Patent Publication No. 2003-249559 describes multiple layers of power supply wires in which each layer includes a high potential power supply wire and a low potential power supply wire that are parallel and adjacent to each other. The wires of an upper layer traverse the wires of a lower layer. A contact wire connects power supply wires, which are located in the upper layer and the lower layer and have the same potential.
Japanese Laid-Open Patent Publication No. 2004-241762 describes multiple layers of power supply wires in which each layer includes a high potential power supply wire and a low potential power supply wire that are parallel and adjacent to each other. The wires of an upper layer are parallel to the wires of a lower layer.